基于扰动观测的4WSS电驱动无人农机路径跟踪控制方法  

Path tracking control method for 4WSS unmanned agricultural machinery based on disturbance observation

作　　者：景亮[1] 冯瑞 沈跃[1] 刘慧[1] 何思伟 张亚飞 JING Liang;FENG Rui;SHEN Yue;LIU Hui;HE Siwei;ZHANG Yafei(School of Electrical and Information Engineering,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]江苏大学电气信息工程学院,镇江212013

出　　处：《农业工程学报》2024年第23期73-81,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(51975260)。

摘　　要：为提高四轮独立自转向(four-wheel self-steering,4WSS)电驱动无人农机复杂农田环境下路径跟踪控制精度与抗扰动能力,该研究提出一种基于非线性扰动观测器的非奇异快速自适应终端滑模复合控制方法。首先,考虑到农田环境下驱动轮滑移对底盘运动规律的影响,建立包含未知侧滑速度与转向滑移角的4WSS无人农机底盘扩展运动学模型;其次,设计非线性扰动观测器,估计底盘扩展运动学模型中包含未知滑移参数的外部集总扰动,并引入到滑模面中进行扰动补偿。在此基础上,针对非奇异快速终端滑模控制的抖振问题,基于指数趋近律构建一种非线性自适应滑模趋近律,保证控制器输出转向执行机构可接受的平滑控制量,并严格证明了所提出复合控制器的稳定性。最后,分别在农田环境下进行直播作业和喷雾作业场地试验,结果表明:当4WSS无人农机以0.4和0.6 m/s的速度跟踪U形目标路径时,相较于传统非奇异快速终端滑模控制方法,直播作业模式下该方法在不同速度下目标作业路径跟踪的横向误差标准差分别为8.1和9.2 cm。喷雾作业模式下相应的横向误差标准差分别为5.3和7.8 cm。所提方法有效提高了复杂农田场景下4WSS无人农机路径跟踪控制的鲁棒性与精度,且具备良好的抗扰动能力和较强的自适应能力,满足农业生产的需求。Agricultural and rural modernization has been ever accelerating with the promotion of rural revitalization strategy.The transformation of agriculture to intelligence,precision,and environmental protection has been the main trend of development in recent years.Among them,autonomous navigation of unmanned agricultural machinery has drawn much attention to effectively improve accuracy and efficiency.Path tracking control is one of the key technologies in the autonomous navigation of agricultural machinery.A lot of research has been done under relatively ideal working conditions.However,agricultural machinery has to operate in complex and various soil conditions,as well as highly unstructured farmland environments,such as muddy paddy fields,rugged slopes,and slippery grasslands.Agricultural machinery can inevitably encounter various uncertain disturbances during operation in these scenarios,leading to the low accuracy of path tracking and the stability of the control system.Therefore,anti-disturbance and strong self-adaptability are required in the autonomous navigation control of agricultural machinery.This study aims to improve the path following control accuracy and antidisturbance ability of four-wheel self-steering(4WSS)electrically driven unmanned agricultural machinery in complex farmland environments.A control system of non-singular fast adaptive terminal sliding mode was also proposed using a nonlinear disturbance observer.Firstly,a 4WSS chassis extended kinematic tracking error model of unmanned agricultural machinery was established to consider the influence of drive wheel slip on the chassis motion in the farmland environment,including unknown sideslip speed and steering slip angle.Secondly,a nonlinear disturbance observer was designed to estimate the external lumped disturbance with unknown slip parameters,according to the chassis extended kinematic tracking error model.The disturbance compensation was introduced into the controller.A nonlinear adaptive sliding mode was also constructed to slow down the

关 键 词：控制 无人农机 路径跟踪 非线性扰动 观测器 非奇异快速自适应 终端滑模控制 

分 类 号：S49[农业科学—植物保护]